Automatic control system for dynamoelectric machines



June 28, 1949.

2 a. ma L n mFM H n--. wmm 2 v9 8 i m W. F. FELL ET AL AUTOMATIC CONTROL SYSTEM FOR DYNAMOELECTRIC MACHINES Original Filed Aug. 10, 1945 Patented June 28, 1949 AUTOMATIC CONTROL SYSTEM FOR DYNAMOELECTRIC MACHINES William F. Fell and Evan S. Smith, Hasbrouck Heights, N. J., assignors to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Original application August 10, 1943, Serial No.

Divided and this application February 19, 1946, Serial No. 648,782

2 Claims. 1

The present application is a division of copending application Serial No. 498,122, filed August 10, 1943, now abandoned, and relates to automatic control systems for dynamo electric machines and more particularly to the regulation of the current flow in the field of a dynamo electric machine or series of machines for purposes of regulating the voltage thereof and maintaining the load properly divided between the machines after they are connected in parallel.

An object of the invention is to provide an improved method of regulation of the voltage of a. current generator.

Another object of the invention is to provide an improved regulating system involving a novel combination and inter-relationship of elements functioning as a unit to provide the desired regulation for a series of generators operating in parallel relationship to supply a common load.

Another object of the invention is to provide a novel system of control for a plurality of sources of current whereby the voltage of the sources of current may be maintained at a substantially constant value, including means for varying the voltage setting of the sources so as to elfect a predetermined load division between the respective sources by balancing the setting of the respective sources.

Another object of the invention is to provide a novel arrangement for varying the datum or volt age setting of the voltage regulating means dependent upon the operating condition of the source of electrical energy in relation to the load.

These and other objects of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawing. It is to be understood, however, that the drawing is for the purpose of illustration only, and is not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

The drawing is a diagrammaticview of a system cmbochring the present invention.

Referring to the drawing, numeral l indicates a generator of conventional type including an armature and commutator 2 and shunt field winding 2.

The generator I has suitable terminals A, B, C and D. The terminal B is connected through a suitable conductor 5 to a shunt field winding 3 while the opposite end of the shunt iield winding I is connected through a conductor 6 to negative output brushes on the commutator 2 suitably interconnected by a conductor I. The commutator 2 has also provided positive output brushes 2 suitably connected by a conductor 8. The conductor 8 is connected by a conductor 9 to a positive output generator terminal A, while the conductor I is connected by a conductor ID to a generator terminal C, and by a conductor 4 to the negative output generator terminal D.

Leading from the field generator terminal B of the generator I is a conductor H which leads to a terminal l2 on a regulator Hi. There also leads from the terminal C of the generator I a conductor 14 which is connected to regulator terminal l5.

Leading from the negative output terminal D of generator I, is a conductor l6 which leads to a terminal ll of the regulator [3.

A conductor I8 leads from the positive output generator terminal A to a regulator terminal IS. The generator I is controlled by the voltage regulator l3, including a variable resistance carbon pile element 20 connected at one end by an electrical conductor 2| to terminal I 2 and through the conductor I I to the field terminal B of the generator l. The opposite end of the variable resistance element 20 is connected by conductor 22 to conductor 23 which interconnects regulator ter-- minal l9 and a regulator terminal 24. Thus the conductor 22 leads through the conductor 23, terminal l9 and conductor l8 to the terminal A of the generator i and thereby to the positive output terminal of the generator I.

Thus the carbon .pile 20 regulates the excitation of the field winding 3, of the. generator I. The resistance of the carbon pile 20 is regulated by suitable electromagnetic windings arranged so as to control an armature 25 and thereby the pres-{ sure applied to the carbon pile 20 and the re-. sistance thereof.

The regulator is shown diagrammatically in the drawing as including the armature 25 pivoted at 26 and exerting a compressive force upon the carbon pile 20 under tension of a spring 21. The spring 21 is arranged so as to balance the electro magnetic force applied on the armature 25 by an electromagnetic coil or winding 28 when energized by a voltage of a predetermined value and is pref erably of a type such as shown in the patent application Serial No. 498,122 filed August 10, 1943. The coil 28 is connected at one end by a conductor 29 including suitable ballast resistors 30 and ill," to a terminal 32 and through conductor 33 to the terminal I! and thereby through conductor l6," terminal D andconductor 4 to the negative ter-" minal of generator i. I

The opposite end of the winding 28 is con-' nected by a conductor 34 to the conductor 23 which is connected by a conductor Ii which in turn is connected to terminal is and to the posi tive output terminal A o! the generator i. Thus the coil II responds to the output voltage of the generator i across terminals A and D and is arranged to regulate the carbon pile 20 so as to control the excitation of the field winding 3 of the generator I so as to maintain a predetermined generator output voltage.

A second electromagnetic coil or winding 35 is provided for varying the datum or voltage setting of the winding 2|. The winding 35 has one end connected by a conductor 36 to a terminal 31. The other end of the Winding 35 is connected by a conductor 38 to a point intermediate the opposite ends of a voltage dividing resistor arrangement including the resistors 39 and ll. The resistor 40 has its opposite end connected to the conductor 33 while the opposite end of the resistor 33 is connected through an adjustable arm I to a terminal i5. It will be seen then that the resistors 39 and 40 are connected in parallel with leads 4, l6 and 33 through conductors l4 and iii, respectively.

A plurality of generators l, IA, IB and K3 are provided as shown and each of the generators IA, IB and IC has a regulator similar to the regulator ll of the generator i and indicated herein as IIA, I38 and HG, respectively. Likewise, i'or simplicity of illustration, the corresponding connections of the regulator circuits of the generators IA, ID and iC are indicated by like numerals bearing a letter A, B, or C corresponding to the respective generator to which the same relates. The lines 33, 33A, 33B and 330 are grounded at the terminals 32, 32A, 32B and 32C so as to provide a common potential at such point.

The coil ll is connected to a similar coil 35A, "B, and "C in each of the regulators I3A, i3B and "C respectively, through an equalizer bus line 42. Through the arrangement of the voltage dividing resistors and 40 connected across the leads I, II and 38, it will be seen that the coil Ii connected thereto through conductor 38 is responsive to the voltage drop across the leads 4, II and 33 which have suilicient inherent resistance so that a decrease or increase in the voltage setting of the regulator i3 will result dependent upon the relative outputs of the several generators.

The windings IIA, "B and 35C in each of the respective regulators "A, B and NC corresponding to the winding II in regulator i3 are so designed that upon the generator controlled by any one of the regulators l3 assuming a greater portion of the load than the other generators the voltage drop across the inherent resistance of the lines 4, I and 33 of such generator will exceed the voltage drop across the lines I, II and II of the several other generators, whereupon a current will flow in the winding 35 of the regulator for the first mentioned generator in a like'direction to the current flow in the winding II causing an increase in the magnetic force acting upon the armature 25 and increasing the resistance of the carbon pile 20 so as to reduce the voltage produced by the generator controlled thereby. The windings 28 and II are wound in relation one to the other so as to assure this action.

The direction 01' current flow through the winding II of the other regulators i3, however, will be'in a direction opposite to that in its corresponding winding 2. so as to counteract the electromagnetic force of the main control winding '4 28 and thereby cause the spring I! to tend to draw the armature II in a direction for decreasing the resistance or the carbon pile 2| so as to increase the voltage produced by the generator controlled by the some until the several generators are in a balanced relation.

The voltage coils II of the regulators IS, BA, BB, and I30 of the generators I, IA, ID, IC, respectively, are so calibrated as to regulate their respective generators so as to maintain substantially the same voltage.

Main output lines 3 and Il lead from the terminals 24 and I! of the regulator II. Switches 45, 45A, 45B and C control the connection of'the respective generators to a. suitable load through load lines ll and 41.

The adjustable resistances 39 in the several regulators provide a means whereby the voltage drop inherent in the several leads 33, II and 4 may be divided so that suitable adjustment may be made for variance in the inherent resistance of leads I3, I and l of the several generators, thereby permitting a balance of the load currents provided by the several generators during a normal division of the load.

From the foregoing, it will be seen that we have provided through the latter system a novel means for maintaining a proper division of load between the several generators.

Although only one embodiment of the invention has been illustrated and described, various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is therefore, to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In combination, a load circuit, a, plurality of generators, meam connecting said generators to said load circuit, a regulator associated with each of said generators, each regulator including a variable resistance carbon pile element arranged to control the voltage output of its associated generator, electromagnetic means for varying the resistance or said carbon pile element, said electromagnetic means including a first windin connected across the output of its associated generator to regulate said carbon pile element so as to maintain a substantially constant voltage output from said associated generator, and a second winding for varying the voltage setting of said first winding, circuit means interconnecting the second winding of each regulator to the second winding of the other of said regulators, said circuit means including line resistance in the output circuit oi each generator, a voltage dividing means connected across said line resistance and arranged in said circuit means in such a manner that upon a diiierence in the voltage drop across the line resistances of said regulators there may be elected a current flow through said second windings in such a direction as to tend to maintain a predetermined division of load between the respective generators, and said voltage dividing means including an adjustable resistance for electing an initial balance of the load currents provided by the several generators upon a predetermined division of the load.

2. In an electrical control system of the class including a load circuit, a plurality oi generators for said load circuit, means to connect the output of said generators to said load circuit, a regulator associated with each of said generators, each regulator including a main control coil and a of said voltage dividing resistor so that upon an unbalanced relationship in the voltage drop across the respective line resistances of the generators there may be eil'ected a current flow through the compensating coils of the regulators of said generators in such a direction as to tend to'maintain a predetermined divisbn of load between the respective generators, and each of said 8 voltage dividing resistors including an adjustable resistance element to set the division of load between the respective generators under varying operating conditions.

WIILIAM F. FELL. EVAN S. sm'rn.

REFERENCES CITED The following references are of record in the die of this patent:

UNITED STATES PATENTS Number Name Date I 1,400,502 Turbayne Dec. 13, 1921 1,760,088 Seeger Hay 2'7, 1930 2,401,795 Rady June 11, 1946 FOREIGN PATENTS Number Country Date 66,202 Switzerland Nov. 14, 1913 

